Crank for internal-combustion motors



May 20, 1924. 1,494,389

R. J. STAPLES ET AL CRANK FOR INTERNAL COMBUSTION MOTORS Filed Dec. 27 19?.)

Patented May 20, 1924.

STATES 1,494,3se I TENT OFFICE.

ROBERT J. STAPLES AND AUBREY 0. JENNINGS, or HUMBLE, Tunas.

cnANK non INTERNAL-COMBUSTION MOTORS.

Application filed December 27, 1921. Serial No.525,003.

To all whom it may concern:

Be it known that we, ROBERT J. STAPLES and AUBREY C. JENNINGS, citizens of the United States, residing at Humble, in the county of Harris and State of Texas, have invented certain new and useful Improvements in a Crank for Internal-Combustion Motors, of which the following is a specification.

This invention relates to new and useful improvements. in a crank for internal combustion motors. 1

One object of the invention is to provide a crank especially designed for starting an internal combustion motor and which, in case of a back kick of the motor will be automatically disconnected from the motor thus avoiding injury to one cranking the motor.

Another object of the invention is to provide a crank of the character described which is of simple construction, which may be cheaply and easily manufactured and which is positive in action.

With the above and other objects in view the invention has particular relation to certain novel features of construction, operation, and arrangement of parts, an example of which is given in this specification and illustrated. in the accompanying drawings wherein Figure 1 shows a side view of the crank as applied to the motor.

Figure 2 shows an inner end View of the said crank.

Figure 3 shows an outer end view of a specially formed ratchet employed, and Figure 41- shows a fragmentary view showing the ratchet and the adjacent end of the crank in section.

Referring now more particularly to the drawings the numeral 1 designates a motor case. Numeral 2 designates a motor crank shaft whose forward end isforined into a one way clutch 3, the numeral 4 designates a crank. adapted to be inserted through and to operate in a bearing 5, aligned with the crank shaft and formed in the front end of the case 1; the numeral 6 designates a ratchet which is rotatably mounted on the reduced spindle 7 into which the inner end of the crank t is formed. An annular shoulder 18 is formed on the crank by reducing the same to form the spindle 7. This ratchet has a limited lengthwise movement on the spindle and is held against detachmg sockets 12, 12 provided to receive the corresponding shoulders 13, 13, carried by the crank on opposite sides of the spindle 7.

A dog 14 is fastened on thesliding rod 15 which slides in aligned bearings 16, 16 carried by the case 1. The free end of this dog is adapted to engage behind the teeth 10 of the ratchet and is normally held in this position'by means of the pull spring 7, one end of which is attached to said dog and the other end of which is attached to the case 1 beneath and in the rear of said dog.

In operation the crank is inserted through the bearing 5, in the usual way, the inner end of the ratchet clutching with the forward end of the motor shaft 2 and the shoulders 13 seating in the sockets 12. The motor may now be cranked by turning the crank 4 in the usual way, the dog 14: dropping successively behind the teeth 10. In case of backfire or back kick of the motor the ratchet 6 will remain clutched with the crank shaft and will he suddenly turned backwardly and the spiralled form, or pitch, of the teeth 10 will force the dog 14 suddenly into contact with the opposing shoulder 18 of the crank. The dog it will pass beyond the teeth 10 and will force the crank outwardly relative to the ratchet 6 and disengage the shoulders 13 from the sockets 12 thus disconnecting the crank from the ratchet 6 and from the motor and preventing reverse rotation of the crank and thus avoiding injury to the operator of it. The dog 14 operates idly except when forced by the teeth 10 into contact with the shoulder 18 with the result explained.

What we claim is:

1. A crank for internal combustion motors, a ratchet having spiralled teeth rotatably mounted on the inner end of said crank, said ratchet having a limited lengthwise movement relative to the crank, and a dog disposed to engage with the teeth of said ratchet and on reverse rotation thereof to move the same lengthwise on said crank.

2. A crank for internal combustion motors, a ratchet formed with spiralled teeth and rotatably mounted on the inner end of said crank and having. a limited lengthwise movement relative thereto, interlocking means formed at the adjacent ends of said crank and ratchet, and a slidably mounted dog engaging with the ratchet and operating to move the same lengthwise on the crank on reverse rotation of the ratchet.

3. A crank for internal combustion molUl'S, a ratchet formed with spiralled teeth and rotatahly mounted on the inner end of said crank and having a limited lengthwise movement relative thereto, interlocking means formed at the adjacent ends of said crank and ratchet, the other end of said ratchet being formed to clutch with the motor crank shaft, and a dog disposed to disconnect the ratchet from the crank on reverse rotation thereof.

4-. The combination with amotor having a crank shaft one end of which is formed into a clutch member, a crank, a ratchet formed With spiralled teeth rotatably mounted on the inner end of said crank and having a limited lengthwise movement relative thereto and Whose end, adjacent the motor shaft is formed to clutch with said shaft, interlocking means carried by the rrank and the adjacent end of said ratchet, a dog whose free end normally engages behind said ratchet teeth, and upon reverse rotation of the ratchet disen'gages said interlocking means.

5. Thecombination With a motor having a crank shaft one end of which is formed into a clutch member, a crank, a ratchet formed with spiralled teeth rotatably mounted on the inner end of said crank and having a limited lengthwise movement relatire thereto and Whose end, adjacent the motor shaft is formed to clutch with said shaft, interlocking means carried by the crank and the adjacent end of said ratchet and a dog whose free end normally engages behind said ratchet teeth, and a yieldable member connected to said dog. and normally holding it in position to engage Withsaid teeth, said dog on reverse rotation of said ratchet operating to disengage said ratchet from said crank.

In testimony whereof We have signed our names to this specification in the presence of two subscribing witnesses.

ROBERT J. STAPLES. AUBREY C. JENNINGS. Witnesses J NO. B. OLIVER, E. V. HARDWAY. 

